The Bain News Service photograph collection at the Library of Congress
The Library of Congress has been scanning images from the Bain News Service that are on glass negatives and posting them to Flickr Commons to use crowd sourcing to figure out who the people are that are named in the images. They post the images to Flickr Commons each Friday.
I just did a quick calculation. There are 40,000 Bain negatives according to the Library of Congress website. If they are releasing them at a rate of 40 per week it will take 1,000 weeks to complete the project. With 52 weeks in the year it will take 19.2 years to complete the project. We can round that up to 20 years since most weeks there are less than 40, and for several weeks none were posted.
The LOC also has a newspaper scanning project that is equally slow paced. Google Books started in 2004 and has already scanned 10 millions books by the end of 2009.